Process For Producing Decorative Sheet, Decorative Sheet, And Decorative Molded Article Obtained Using Same

ABSTRACT

A decorative sheet includes a design layer, a primer layer and a surface protective layer formed by cross-linking and curing an ionizing radiation curable resin composition in this order on a base material. A surface of the surface protective layer is smooth. In one aspect, a ten point average roughness RzJIS on a rear face of the decorative sheet and a thickness T of the base material satisfies the following equation (I); and an arithmetic average roughness Ra on the rear face and a thickness T of the base material satisfies the following equation (II): 
         T ×0.30≧ RzJIS   (I)
 
         T ×0.20≧ Ra≧T ×0.005  (II).
 
     In another aspect, an arithmetic average roughness Ra on a rear face of the decorative sheet is 1.0 to 10.0 μm.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. application Ser.No. 13/807,081, filed Dec. 27, 2012, which is a 371 ofPCT/JP2011/065084, filed Jun. 30, 2011, the contents of each of whichare incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a production process for a decorativesheet used for decorative molded articles of various applications suchas buildings, vehicles, fittings and the like, a decorative sheet and adecorative molded article prepared by using the same.

RELATED ART

Decorative molded articles decorated by laminating decorative sheets onthe surfaces of molded articles are used for various applications suchas members for buildings, vehicle interior parts and the like. Adecorative sheet used for the above decorative molded articles isproduced usually by laminating a design layer and a surface protectivelayer in order on a base material.

In the above production process, however, irregularities are produced ona surface thereof when a design layer is formed, and when a surfaceprotective layer is laminated thereon, a smoothness of the surfaceprotective layer is likely to be damaged.

On the other hand, proposed in a patent document 1 are skin materialsfor automobile interior containing a thermoplastic resin basecoat/transparent coating film which is stuck on an outside surface of athermoplastically moldable semi-rigid resin backing sheet. It isdescribed therein that the base coat and the transparent coating filmdescribed above are coated on a matting career and dried and that theyare then transferred on the backing sheet described above and laminatedthereon. In the patent document 1, however, a gloss of the transparentcoat depends on a smoothness of the matting career, and therefore theproblem that it is difficult to finely control the smoothness is broughtabout.

Further, if a decorative sheet is not at all subjected to smoothingtreatment as used to be in the past, a smoothness and a gloss of thedecorative sheet are notably different from a smoothness and a gloss ofthe decorative molded article after injection molding, and therefore adesign feeling of the decorative sheet is different from a designfeeling of the decorative molded article to a large extent.

-   Patent document 1: Japanese Patent Application Laid-Open (through    PCT) No. 512225/2000

DISCLOSURE OF THE INVENTION

In order to solve the problems described above, it is considered that ametal plate subjected to mirror treatment after laminating a surfaceprotective layer is used to be subjected to smoothing treatment by hotpress processing and the like as a method for providing a surface of asurface protective layer with a smoothness and a gloss. However, even ifa surface of a surface protective layer is smoothed, irregularities of adesign layer remain, and therefore when a decorative sheet is heated ininsert molding and injection molding simultaneous decoration to allowthe surface protective layer to be softened, the irregularities of thedesign layer come up to the surface protective layer, so that asmoothness and a gloss on a surface of the decorative molded article arelikely to be damaged. That is, a high smoothness and a high gloss of thedecorative sheet are reduced after injection molding and different froma smoothness and a gloss of the decorative molded article afterinjection molding, and a design feeling of the decorative sheet islikely to be different from a design feeling of the decorative moldedarticle.

In light of the problems described above, the present inventors havefiled a patent (Japanese Patent Application No. 088099/2009) related toa production process for a decorative sheet of a high gloss which keepsa surface smoothness and a gloss and maintains a design feeling evenafter three-dimensional molding such as insert molding, injectionmolding simultaneous decoration and the like. However, they have foundthat involved therein are the problems that when both surfaces of adecorative sheet are smoothed by a step in which the surfaces of adesign layer and a primer layer are smoothed, small dusts and rubbishesare wrapped in a roll of the decorative sheet produced to generate dentsand wounds and that a surface and a back face of the decorative sheetare tightly adhered with each other to generate scratches and wrinkles.

In light of the problems described above, an object of the presentinvention is to provide a production process for a decorative sheet of ahigh gloss which keeps a surface smoothness and a gloss and maintains adesign feeling even after three-dimensional molding such as insertmolding, injection molding simultaneous decoration and the like andwhich is less liable to generate dents and wounds by wrapping thereinforeign matters even when winding the decorative sheet on a roll andless liable to produce scratches and wrinkles by bringing a surface anda rear face of the decorative sheet into close contact with each other.

Intensive researches repeated by the present inventors in order to solvethe problems described above have resulted in finding that the problemsdescribed above can be solved by carrying out smoothing treatment beforelaminating a surface protective layer and subjecting a rear face toroughening treatment. In particular, they have found that the problemsdescribed above can be solved by carrying out the roughening treatmentso that a ten point average roughness RzJIS of the rear face and athickness of the base material and an arithmetic average roughness Ra ofthe rear face and a thickness of the base material satisfy specificequations respectively. The present invention has been completed basedthe above knowledge.

That is, the present invention provides the following items:

[1] a production process for a decorative sheet comprising a step inwhich a primer layer is formed on a releasing film having a smoothsurface, a step in which a design layer is formed on the above primerlayer, a step in which the primer layer and the design layer aretransferred on a base material, a step in which the releasing film onthe base material is peeled off, a step in which an ionizing radiationcurable resin composition is laminated on the primer layer formed on thebase material and a step in which the above ionizing radiation curableresin composition is cross-linked and cured to form a surface protectivelayer, wherein it further comprises a roughening treatment step in whicha ten point average roughness RzJIS on a rear face of the decorativesheet and a thickness T of the base material are controlled to satisfythe following equation (I) and in which an arithmetic average roughnessRa on the rear face and a thickness T of the base material arecontrolled to satisfy the following equation (II):

T×0.30≧RzJIS  (I)

T×0.20≧Ra≧T×0.005  (II)

[2] a production process for a decorative sheet comprising a step inwhich a primer layer is formed on a releasing film having a smoothsurface, a step in which a design layer is formed on the above primerlayer, a step in which the primer layer and the design layer aretransferred on a base material, a step in which the releasing film onthe base material is peeled off, a step in which an ionizing radiationcurable resin composition is laminated on the primer layer formed on thebase material and a step in which the above ionizing radiation curableresin composition is cross-linked and cured to form a surface protectivelayer, wherein it further comprises a roughening treatment step in whichan arithmetic average roughness Ra on a rear face of the decorativesheet is controlled to 1.0 to 10.0 μm,[3] a decorative sheet comprising a design layer, a primer layer and asurface protective layer formed by cross-linking and curing an ionizingradiation curable resin composition in this order on a base material,wherein a surface of the surface protective layer is smooth; a ten pointaverage roughness RzJIS on a rear face of the decorative sheet and athickness T of the base material satisfies the following equation (I);and an arithmetic average roughness Ra on the rear face and a thicknessT of the base material satisfies the following equation (II):

T×0.30≧RzJIS  (I)

T×0.20≧Ra≧T×0.005  (II)

[4] a decorative sheet comprising a design layer, a primer layer and asurface protective layer formed by cross-linking and curing an ionizingradiation curable resin composition in this order on a base material,wherein a surface of the surface protective layer is smooth, and anarithmetic average roughness Ra on a rear face of the decorative sheetis 1.0 to 10.0 μm.

According to the production process of the present invention for adecorative sheet, there has been obtained a decorative sheet of a highgloss which keeps a surface smoothness and a gloss and maintains adesign feeling even after three-dimensional molding such as insertmolding, injection molding simultaneous decoration and the like andwhich is less liable to generate dents and wounds by wrapping thereinforeign matters even when winding the decorative sheet on a roll andless liable to produce scratches and wrinkles by allowing a surface anda rear face of the decorative sheet to be tightly adhered with eachother. When the above decorative sheet was actually produced, wounds anddents generated by wrapping therein foreign matters were inhibited, andblocking between a surface and a rear face of the decorative sheet wasrestrained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a step drawing showing one embodiment of the invention in theproduction process of the present invention for a decorative sheet.

FIG. 2 is a step drawing showing one embodiment of the invention in theproduction process of the present invention for a decorative sheet.

EXPLANATION OF THE CODES

-   10 Decorative sheet-   11 Releasing film-   12 Primer layer-   13 Design layer-   14 Base material-   15 Surface protective layer-   16 Fine particle-containing resin layer

BEST MODE FOR CARRYING OUT THE INVENTION

The production process of the present invention for a decorative sheetis characterized by comprising a step in which a primer layer is formedon a releasing film having a smooth surface, a step in which a designlayer is formed on the above primer layer, a step in which the primerlayer and the design layer are transferred on a base material, a step inwhich the releasing film on the base material is peeled off, a step inwhich an ionizing radiation curable resin composition is laminated onthe primer layer formed on the base material, a step in which the aboveionizing radiation curable resin composition is cross-linked and curedto form a surface protective layer and a roughening treatment step inwhich a ten point average roughness RzJIS on a rear face of thedecorative sheet and a thickness T of the base material are controlledto satisfy the equation (I) described above and in which an arithmeticaverage roughness Ra on the rear face and a thickness T of the basematerial are controlled to satisfy the equation (II) described above ora roughening treatment step in which an arithmetic average roughness Raon a rear face of the decorative sheet is controlled to 1.0 to 10.0 μm.The production process of the present invention shall be explained belowin detail by using FIG. 1 and FIG. 2.

FIG. 1 and FIG. 2 are step drawings showing the outline of theproduction process of the present invention for a decorative sheet. Theproduction process of the present invention comprises at least thefollowing steps (1) to (7).

(1) Step in which a primer layer is formed on a releasing film:

A primer composition is laminated on a releasing film 11 having a smoothsurface and then dried, if necessary, whereby a primer layer 12 isformed.

In the present invention, a smooth surface of the releasing film meansthat it has an arithmetic average roughness (Ra) of 0.5 μm or less,preferably 0.2 μm or less. In this regard, the arithmetic averageroughness (Ra) means an arithmetic average roughness Ra prescribed inJIS B 0601: 2001.

Also, a smoothness of the decorative sheet of the present invention ispreferably 0.5 μm or less, more preferably 0.2 μm or less in terms of anarithmetic average roughness Ra.

In respect to a laminating method for the primer layer 12, it can beformed by a coating method, and a transfer method can be used as well.When the primer layer 12 is formed by the coating method, capable ofbeing used are gravure coating, gravure reverse coating, gravure offsetcoating, spin coating, roll coating, reverse roll coating, kiss coating,wheeler coating, dip coating, solid coating by a silk screen, wire barcoating, flow coating, comma coating, overflow coating, brush coating,spray coating and the like. The transfer method is a method in which acoating film of a primer layer is once formed on a thin sheet (film basematerial) and then coated on the surface of the base material, and itincludes a laminate method in which a coating film of a coatingcomposition is adhered on a steric matter together with a base materialand a transfer method in which a coating film and a transfer sheethaving, if necessary, an adhesive layer formed thereon are adhered onceon a releasable support sheet and in which only the support sheet isthen peeled off.

(2) Step in which a design layer is formed on the primer layer:

Next, an ink for design is printed or coated on the primer layer 12 andthen dried, if necessary, to thereby form a design layer 13. The designlayer 13 comprises a picture layer and/or a whole face solid coloredlayer.

(3) Step in which the primer layer and the design layer are transferredon a base material:

Then, the primer layer 12 and the design layer 13 which are formed onthe releasing film 11 are transferred onto a base material 14. Hot pressprocessing using a mirror surface plate and emboss processing using amirror surface roll are preferably used as a transfer method thereof. Tobe specific, the releasing film 11 on which the primer layer 12 and thedesign layer 13 are laminated and the base material 14 are heated andsoftened by means of a hot press machine and an emboss processingmachine which are publicly known, and they are compressed in asuperposed state and stuck together. This provides a sheet shown in FIG.1 (a).

(4) Step in which the releasing film on the base material is peeled off:

The releasing film 11 on the base material 14 after transferred ispeeled off, whereby obtained is a sheet in which the design layer 13 andthe primer layer 12 are laminated in this order on the base material 14as shown in FIG. 1 (b). In this case, a surface of the primer layer 12is provided with a smooth surface by receiving a surface form of thereleasing film in the previous step.

(5) Step in which an ionizing radiation curable resin composition islaminated on the primer layer:

Then, an ionizing radiation curable resin composition is laminated bycoating a coating liquid comprising the ionizing radiation curable resincomposition or a coating liquid containing the ionizing radiationcurable resin composition on a smooth surface of the primer layer 12. Aviscosity of the coating liquid shall not specifically be restricted aslong as it is a viscosity at which an uncured resin layer can be formedon a surface of the primer layer 12 by a coating method described later.

In the production process of the present invention, the coating liquidprepared is coated on a surface of the primer layer 12 by a publiclyknown method such as gravure coating, bar coating, roll coating, reverseroll coating, comma coating and the like, preferably gravure coating sothat a thickness thereof after cured is 1 to 30 μm, whereby an uncuredresin layer is formed.

In this regard, the ionizing radiation curable resin means resins whichare cross-linked and cured by irradiating with beams having an energyquantum which can cross-link and polymerize molecules amongelectromagnetic waves or charged particle beams, that is, a UV ray, anelectron beam or the like. To be specific, products suitably selectedfrom polymerizable monomers, polymerizable oligomers or prepolymerswhich have so far conventionally been used as ionizing radiation curableresins can be used.

(6) Step in which the ionizing radiation curable resin composition iscross-linked and cured to form a surface protective layer:

Next, the ionizing radiation curable resin composition is cross-linkedand cured by irradiating the uncured resin layer comprising the ionizingradiation curable resin composition with an electron beam, a UV ray orthe like to form a surface protective layer 15. This makes it possibleto obtain a decorative sheet 10 on which the surface protective layer 15is formed as shown in FIG. 1 (c).

In this regard, when an electron beam is used as the ionizing radiation,an accelerating voltage thereof can suitably be selected according tothe resin used and a thickness of the layer, and the uncured resin layeris preferably cured usually at an accelerating voltage of 70 to 300 kV.

In radiation of the electron beam, the higher the acceleration voltageis, the more the penetrability of the electron beam is increased, andtherefore when the base material 14 which is deteriorated by an electronbeam is used, the accelerating voltage is selected so that a depth ofpenetration of the electron beam is substantially the same as athickness of the resin layer, whereby the electron beam can be inhibitedfrom being irradiated excessively onto the base material 14, anddeterioration of the base material caused by irradiation with anexcessive amount of the electron beam can be allowed to stay in aminimum level.

An irradiation dosage of the electron beam is preferably an amount inwhich a cross-linking density of the resin layer is saturated, and it isselected in a range of usually 5 to 300 kGy (0.5 to 30 Mrad), preferably10 to 100 kGy (1 to 10 Mrad).

Further, the electron beam source shall not specifically be restricted,and capable of being used are various electron beam accelerators such asa Cockroft-Walton type accelerator, a Van de Graft type accelerator, aresonance transformer type accelerator, an insulating core transformertype accelerator, a linear type accelerator, a Dynamitron typeaccelerator, a high frequency type accelerator and the like.

When a UV ray is used as the ionizing radiation, the radiationcontaining a UV ray having a wavelength of 190 to 380 nm is radiated.The UV ray source shall not specifically be restricted, and used are,for example, a high pressure mercury lamp, a low pressure mercury lamp,a metal halide lamp, a carbon arc lamp and the like.

A smoothness of the surface protective layer 13 is preferably 0.01 μm ormore and less than 1.0 μm, more preferably 0.01 to 0.5 μm and furtherpreferably 0.05 to 0.2 μm in terms of an arithmetic average roughnessRa. In this regard, the arithmetic average roughness Ra means anarithmetic average roughness Ra prescribed in JIS B 0601: 2001.

(7) Roughening treatment step for a rear face of the decorative sheet:

The roughening treatment step for a rear face of the decorative sheet inthe present invention shall not specifically be restricted as long as itis a step in which a rear face of the decorative sheet can be roughenedto such an extent as satisfying the equation (I) and the equation (II)each described above and/or to such an extent as satisfying thearithmetic average roughness Ra described above. It includes, forexample, a method in which a rear face side of the decorative sheet 10,to be specific, a face brought into no contact with the design layer 13and the primer layer 12 on the base material 14 is roughened by hotpress using a satin finished plate, emboss processing using a satinfinished roll and sand blast treatment. Publicly known methods can beused for the hot press processing and the emboss processing, and a rearface of the decorative sheet 10 is roughened, as shown in FIG. 1, bysoftening the decorative sheet 10 by heating it at not lower than asoftening temperature of the constituent base material and lower than afusing point or a melting temperature thereof, pressurizing a rear faceside of the decorative sheet 10 to provide it with a form thereof andthen cooling and solidifying the decorative sheet.

Further, the roughening treatment in the present invention includes amethod in which a rear face of the decorative sheet 10 is roughened, asshown in FIG. 2 (d), by providing a fine particle-containing resin layer16.

When a rear face of the decorative sheet is roughened by hot press andemboss processing, a rear face of the decorative sheet can be roughened,to be specific, by carrying out hot press processing using a mirrorplate at a surface side of the base material 14 and using a satinfinished plate at a rear face side thereof and carrying out embossprocessing using a mirror roll at a surface side of the base material 14and using a satin finished roll at a rear face side thereof (refer toFIG. 1). To be more specific, when the primer layer 12 and the designlayer 13 are transferred onto the base material 14, hot press processingis carried out by using a mirror plate at a releasing film 11 side and asatin finished plate at a base material 14 side, and emboss processingis carried out by using a mirror roll at a releasing film 11 side and asatin finished roll at a base material 14 side, whereby the primer layer12 and the design layer 13 are transferred onto the base material 14,and at the same time, a rear face of the decorative sheet 10 can beroughened.

RzJIS and Ra on the surface to be treated can be controlled bycontrolling the hot press temperature and the emboss temperature andcontrolling a surface roughness of the satin finished plate and thesatin finished roll. The hot press temperature and the embosstemperature may be suitably selected according to the base material, andwhen they are 30 to 70° C. in a case of, for example, vinyl chloride,160 to 180° C. in a case of a polypropylene resin and 150 to 260° C. ina case of an acryl base resin, the irregular forms of the satin finishedplate and the satin finished roll can be provided well. An arithmeticaverage roughness Ra of the satin finished plate and the satin finishedroll is preferably 1.0 to 20.0 μm, more preferably 1.0 to 15.0 μm andfurther preferably 1.0 to 10.0 μm.

Sand blast treatment can be carried out by blowing inorganic particlesof silica, titania and the like against the surface to be treated (arear face of the decorative sheet 10) by making use of compressed air.It is carried out preferably after the step (3) described above since anarithmetic average roughness Ra on a rear face of the decorative sheet10 is liable to be kept at a high level. RzJIS and Ra of the surface tobe treated can be controlled by controlling a particle diameter of theinorganic particles and a blowing amount thereof.

A method for providing the fine particle-containing resin layer 16 on arear face of the decorative sheet 10 includes a method in which a resincomposition containing a binder resin and fine particles is laminated bythe coating method and transfer method each described above (refer toFIG. 2 (d).

When providing the fine particle-containing resin layer 16 on a rearface of the decorative sheet 10, it can be carried out before or afterany step of the steps (1) to (6), and it is carried out preferably afterthe step (3) described above since an arithmetic average roughness Ra ona rear face of the decorative sheet 10 is liable to be kept at a highlevel. RzJIS and Ra of the surface to be treated can be controlled bycontrolling a blend ratio of the fine particles to the binder resin anda particle diameter of the fine particles.

In the roughening treatment for a rear face of the decorative sheet 10in the present invention, an arithmetic average roughness Ra of the rearface is controlled to preferably 1.0 to 10.0 μm, more preferably 1.0 to9.0 μm and further preferably 1.2 to 8.0 μm. In this regard, thearithmetic average roughness Ra means an arithmetic average roughness Raprescribed in JIS B 0601: 2001.

Also, in the roughening treatment described above, a ten point averageroughness Rz of the rear face is controlled to preferably 1.0 to 100.0μm, more preferably 5.0 to 50.0 μm. In this regard, the ten pointaverage roughness Rz means a ten point average roughness Rz prescribedin JIS B 0601: 2001.

If an arithmetic average roughness Ra on a rear face of the decorativesheet 10 is 1.0 μm or more, the effects of the present invention can beexerted. If it is 10.0 μm or less, a roughness on a rear face of thedecorative sheet 10 does not exert an influence on a surface thereof,and therefore when insert molding is carried out by using, for example,the decorative sheet 10, the resulting molded article is sufficientlyprovided with a smoothness and a surface gloss on a surface thereof andsufficiently provided as well with an adhesive property with theinjection resin.

In the roughening treatment for a rear face of the decorative sheet 10in the present invention, a ten point average roughness RzJIS on therear face and a thickness T of the base material satisfy preferably thefollowing equation (I), more preferably the following equation (I-A) andparticularly preferably the following equation (I-B):

T×0.30≧RzJIS  (I)

T×0.20≧RzJIS  (I-A)

T×0.18≧RzJIS  (I-B)

In the roughening treatment for a rear face of the decorative sheet 10in the present invention, an arithmetic average roughness Ra on the rearface and a thickness T of the base material satisfy preferably thefollowing equation (II), more preferably the following equation (II-A)and particularly preferably the following equation (II-B):

T×0.20≧Ra≧T×0.005  (II)

T×0.18≧Ra≧T×0.02  (II-A)

T×0.15≧Ra≧T×0.03  (II-B)

If an arithmetic average roughness Ra on a rear face of the decorativesheet 10 is less than the ranges described above, dents and wounds arelikely to be generated on a surface thereof by wrapping therein foreignmatters, and scratches and wrinkles are likely to be produced byallowing a surface and a rear face of the decorative sheet to be tightlyadhered with each other. On the other hand, if an arithmetic averageroughness Ra on a rear face of the decorative sheet 10 exceeds theranges described above, an arithmetic average roughness Ra on a rearface of the decorative sheet 10 is too large as compared with athickness of the base material, and therefore when the decorative sheet10 is softened, a roughness on a rear face side thereof exerts aninfluence as well on a surface thereof to bring about the problems thata surface of the resulting molded article is inferior in a smoothnessand a surface gloss when insert molding is carried out by using, forexample, the decorative sheet 10 and that an adhesive property with theinjection resin is inferior.

Also, if the ten point average roughness Rz exceeds, though thearithmetic average roughness Ra is small, the ranges described above,irregularities are likely to be locally generated to cause friction whenthe decorative sheets 10 are superposed, and scratches and the like arelikely to be generated.

The releasing film 11 used in the production process of the presentinvention shall not specifically be restricted as long as it can bereleased (peeled) later even if it is brought into contact with theprimer layer 12. It includes films comprising polyethyleneterephthalate, polyethylene, polypropylene and the like and papers, orfilms and papers prepared by coating (subjected to release treatment)release agents such as silicone and the like on the above polymers. Thereleasing film 11 which is subjected to release treatment is liable tobe peeled off and therefore is preferred.

In the production process of the present invention, the primer layer 12formed on the releasing film 11 has the function of enhancing anadhesive property between the design layer 13 and the surface protectivelayer 15 which are present on the base material 14. Further, smoothing asurface of the primer layer 12 makes it possible to smooth a surface ofthe surface protective layer 15 without exerting an influence of theirregularities of the design layer 13 on the surface protective layer15.

(Meth)acryl resins, urethane resins, (meth)acryl•urethane copolymerresins, vinyl chloride-vinyl acetate copolymers, polyester resins,butyral resins, chlorinated polypropylene, chlorinated polyethylene andthe like are used for a primer composition constituting the primer layer12.

Also, a thickness of the primer layer 12 is preferably 0.1 to 10 μm. Athickness of 0.1 μm or more makes it possible to exert sufficiently theeffect of preventing cracking, breaking, whitening and the like on thesurface protective layer. On the other hand, if a thickness of theprimer layer 12 is 10 μm or less, the coating film is stably dried andcured when the primer layer is coated, and therefore the moldability isnot varied. Accordingly, it is preferred.

Next, the design layer 13 comprising the picture layer and/or the wholeface solid colored layer shown in FIG. 1 serves for providing the resinmolded article with a decorative property. The picture layer is formedby printing various patterns with an ink by means of a printer. Thepatterns include woodgrain patterns, stone-grain patterns imitating thesurfaces of rocks such as a marble pattern (for example, travertinemarble patterns) and the like, fabric patterns imitating a blankettexture pattern and a cloth-like pattern, tiling patterns, brick workpatterns and the like, and they include as well composite patternsthereof such as parquetry patterns, patchwork patterns and the like. Theabove patterns are formed by multi-color printing with process colors ofusual yellow, red, blue and black colors, and in addition thereto, theyare formed as well by multi-color printing with special colors usingplates of individual colors constituting the patterns.

Materials prepared by appropriately mixing a binder with a colorant suchas a pigment, a dye and the like, an extender pigment, a solvent, astabilizer, a plasticizer, a catalyst, a curing agent and the like areused as an ink used for the design layer 13. The above binder shall notspecifically be restricted, and optional ones selected from, forexample, polyurethane base resins (acryl urethane copolymer resins andthe like), vinyl chloride/vinyl acetate base copolymer resins, vinylchloride/vinyl acetate/acryl resin base copolymer resins, chlorinatedpolypropylene base resins, acryl base resins, polyester base resins,polyamide base resins, butyral base resins, polystyrene base resins,nitrocellulose base resins, cellulose acetate base resins and the likeare used alone or in a mixture of two or more kinds thereof.

Used as the colorant are inorganic pigments such as carbon black(Japanese ink), iron black, titanium white, antimony white, chromeyellow, titanium yellow, iron oxide red, cadmium red, ultramarine blue,cobalt blue and the like, organic pigments and dyes such as quinacridonered, isoindolinone yellow, phthalocyanine blue and the like, metallicpigments comprising scale-like foil pieces of aluminum, brass and thelike and pearlescent (pearl) pigments comprising scale-like foil piecesof titanium dioxide-coated mica, basic lead carbonate and the like.

In the present invention, a masking layer may be provided, if necessary,between the design layer 13 and the base material 14. The masking layeris provided for the purpose of preventing an effect from being exertedon the colors of the patterns in the decorative sheet 10 by a change anda dispersion in the color of a surface of the base material 14. Usually,the masking layer is formed in an opaque color in many cases, and aso-called solid printed layer having a thickness of 1 to 20 μm issuitably used as the masking layer. A binder, a colorant and the likewhich are used for the masking layer are the same as those used for thedesign layer 13. When the design layer 13 comprises a whole face solidcolored layer, it may be used as the masking layer.

The base material 14 used in the production process of the presentinvention is selected considering a vacuum molding aptitude and aninjection molding simultaneous decoration aptitude, and to berepresentative, a resin sheet comprising a thermoplastic resin is usedtherefor. Usually used as the above thermoplastic resin are acrylresins, polyolefin base resins such as polypropylene, polyethylene andthe like, polycarbonate resins, acrylonitrile-butadiene-styrene resins(hereinafter referred to as “ABS resins”), vinyl chloride resins,polyester resins and the like. Also, the base material 14 can be used inthe form of a single layer sheet of the above resins or a plural layersheet comprising the same kind or different kinds of the resins.

A thickness of the base material 14 is selected according to the uses,and it is usually 0.03 to 1.0 mm, considering a cost and the like,generally 0.03 to 0.5 mm.

A surface of the base material 14 can be subjected, if desired, tosurface treatment by an oxidation method and the like in order toenhance an adhesive property thereof with the layers provided thereon.

The oxidation method described above includes, for example, coronadischarge treatment, chrome oxidation treatment, flame treatment, hotblast treatment, ozone•UV ray treatment methods and the like. The abovesurface treatments are suitably selected according to the kind of thebase materials, and usually a corona discharge treatment method ispreferably used in terms of effects and an operability.

In the production process of the present invention, a polymerizablemonomer and a polymerizable oligomer and/or prepolymer (hereinafterabbreviated as an oligomer/prepolymer) as the ionizing radiation curableresin used for the ionizing radiation curable resin composition shall beexplained below.

To be representative, the polymerizable monomers are suitably(meth)acrylate base monomers having a radically polymerizableunsaturated group in a molecule, and among them, multifunctional(meth)acrylates are preferred. In this case, “(meth)acrylate” means“acrylate” or “methacrylate”, and other similar monomers have the samemeaning. The multifunctional (meth)acrylates shall not specifically berestricted as long as they are (meth)acrylates having two or moreethylenically unsaturated bonds in a molecule. To be specific, theyinclude ethylene glycol di(meth)acrylate, propylene glycoldi(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanedioldi(meth)acrylate and the like. The above multifunctional (meth)acrylatesmay be used alone or in combination of two or more kinds thereof.

In the present invention, monofunctional (meth)acrylates can suitably beused in combination with the multifunctional (meth)acrylates describedabove for the purpose of reducing a viscosity of the multifunctional(meth)acrylates as long as the effects of the present invention are notdamaged. The monofunctional (meth)acrylates include, for example, methyl(meth)acrylate, ethyl (meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, pentyl(meth)acrylate, hexyl(meth)acrylate,cyclohexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate,lauryl(meth)acrylate, stearyl(meth)acrylate, isobornyl(meth)acrylate andthe like. The above monofunctional (meth)acrylates may be used alone orin combination of two or more kinds thereof.

Next, the polymerizable oligomer/prepolymer includesoligomers/prepolymers having radically polymerizable unsaturated groupsin a molecule, for example, epoxy(meth)acrylate baseoligomers/prepolymers, urethane (meth)acrylate baseoligomers/prepolymers, polyester (meth)acrylate baseoligomers/prepolymers, polyether (meth)acrylate baseoligomers/prepolymers, polycarbonate (meth)acrylate baseoligomers/prepolymers and the like.

Further, the polymerizable oligomers/prepolymers include, in addition tothe above compounds, polybutadiene (meth)acrylate baseoligomers/prepolymers which have a (meth)acrylate group on a side chainof a polybutadiene oligomer/prepolymer and which are highly hydrophobic,silicone (meth)acrylate base oligomers/prepolymers having a polysiloxanebond on a main chain, aminoplast resin (meth)acrylate baseoligomers/prepolymers obtained by modifying an aminoplast resin having alarge number of reactive groups in a small molecule thereof andoligomers/prepolymers having cationically polymerizable functionalgroups in molecules of novolak type epoxy resins, bisphenol type epoxyresins, aliphatic vinyl ethers, aromatic vinyl ethers and the like.

If compounds containing at least polycarbonate (meth)acrylate or acrylsilicone (meth)acrylate and multifunctional (meth)acrylate are used asthe ionizing radiation curable resin composition in the presentinvention, an excellent chemical resistance, an excellent scratchresistance and a good three-dimensional moldability are satisfied at thesame time, and therefore it is preferred in terms of making it possibleto obtain a decorative sheet in which a surface protective layer doesnot suffer cracking and the like and which is liable to bethree-dimensionally molded.

When a compound containing polycarbonate (meth)acrylate andmultifunctional (meth)acrylate is used as the ionizing radiation curableresin composition, a weight ratio of the polycarbonate (meth)acrylate tothe multifunctional (meth)acrylate is preferably 98:2 to 70:30, morepreferably 95:5 to 80:20.

The polycarbonate (meth)acrylate used in the present invention shall notspecifically be restricted, and it may be any one as long as it is acompound having a carbonate bond on a polymer principal chain and having(meth)acrylate on a terminal or a side chain. The above (meth)acrylateis preferably difunctional or more from the viewpoint of cross-linkingand curing.

The polycarbonate (meth)acrylate has a weight average molecular weightof preferably 500 or more, more preferably 1,000 or more and furtherpreferably exceeding 2,000 which is measured by GPC analysis and reducedto standard polystyrene. An upper limit of a weight average molecularweight of the polycarbonate (meth)acrylate shall not specifically berestricted, and it is preferably 100,000 or less, more preferably 50,000or less from the viewpoint of controlling the viscosity so that it doesnot grow too high. From the viewpoint of allowing the scratch resistanceto be consistent with the three-dimensional moldability, it is furtherpreferably exceeding 2,000 and 50,000 or less, particularly preferably5,000 to 20,000.

When a compound containing acryl silicone (meth)acrylate andmultifunctional (meth)acrylate is used as the ionizing radiation curableresin composition, a weight ratio of the acryl silicone (meth)acrylateto the multifunctional (meth)acrylate is preferably 50:50 to 95:5, morepreferably 95:5 to 80:20.

The acryl silicone (meth)acrylate used in the present invention shallnot specifically be restricted, and it may be any one as long as it is acompound in which a part of the acryl resin is substituted with asiloxane bond (Si—O) in a molecule and which has two or more(meth)acryloyloxy groups (acryloyloxy groups or methacryloyloxy groups)as functional groups on a side chain and/or a principal chain terminalof the acryl resin.

The acryl silicone (meth)acrylate has a weight average molecular weightof preferably 1,000 or more, more preferably 2,000 or more which ismeasured by GPC analysis and reduced to standard polystyrene. An upperlimit of a weight average molecular weight of the acryl silicone(meth)acrylate shall not specifically be restricted, and it ispreferably 150,000 or less, more preferably 100,000 or less from theviewpoint of controlling the viscosity so that it does not grow toohigh. From the viewpoint of allowing the three-dimensional moldabilityto be consistent with the chemical resistance and the scratchresistance, it is particularly preferably 2,000 to 100,000.

The multifunctional (meth)acrylate used in the present invention shallnot specifically be restricted as long as it is difunctional or higher(meth)acrylate. However, trifunctional or higher (meth)acrylate ispreferred from the viewpoint of a curing property. In this connection,difunction means having two ethylenically unsaturated bonds((meth)acryloyl groups) in a molecule.

Also, the multifunctional (meth)acrylate may be either of an oligomerand a monomer, but it is preferably a multifunctional (meth)acrylateoligomer from the viewpoint of enhancing the three-dimensionalmoldability.

The multifunctional (meth)acrylate has a weight average molecular weightof preferably 500 or more, more preferably 1,000 or more and furtherpreferably exceeding 2,000 which is measured by GPC analysis and reducedto standard polystyrene. An upper limit of a weight average molecularweight of the multifunctional (meth)acrylate shall not specifically berestricted, and it is preferably 100,000 or less, more preferably 50,000or less from the viewpoint of controlling the viscosity so that it doesnot grow too high. From the viewpoint of allowing the scratch resistanceto be consistent with the three-dimensional moldability, it is furtherpreferably exceeding 2,000 and 50,000 or less, particularly preferably5,000 to 20,000.

The multifunctional (meth)acrylate described above includes, forexample, urethane (meth)acrylate base oligomers, epoxy(meth)acrylatebase oligomers, polyester (meth)acrylate base oligomers, polyether(meth)acrylate base oligomers and the like. In this connection, theurethane (meth)acrylate base oligomers can be obtained by reacting, forexample, polyetherpolyol and polyesterpolyol with polyisocyanate toobtain a polyurethane oligomer and esterifying the polyurethane oligomerby (meth)acrylic acid.

Further, other multifunctional (meth)acrylates include polybutadiene(meth)acrylate base oligomers which have a (meth)acrylate group on aside chain of a polybutadiene oligomer and which are highly hydrophobic,silicone (meth)acrylate base oligomers having a polysiloxane bond on amain chain, aminoplast resin (meth)acrylate base oligomers obtained bymodifying an aminoplast resin having a large number of reactive groupsin a small molecule thereof and the like.

When a UV ray curable resin is used as the ionizing radiation curableresin, a photopolymerization initiator is used preferably in an amountof 0.1 to 5 parts by mass based on 100 parts by mass of the resin. Thephotopolymerization initiator can be selected from products which haveso far been conventionally used and shall not specifically berestricted.

Also, p-dimethylbenzoic acid esters, tertiary amines, thiol basesensitizers and the like can be used as a photosensitizer.

In the present invention, an electron beam curable resin is preferablyused as the ionizing radiation curable resin. The electron beam curableresin can be used in the absence of a solvent and is more preferred fromthe viewpoint of environmental protection and human health. Further, itdoes not require a photopolymerization initiator and provides a stablecuring characteristic.

Other resins can be added to the ionizing radiation curable resincomposition described above as long as the effects of the presentinvention are displayed. For example, when the decorative sheet 10obtained by the production process of the present invention is intendedto be provided with a flexibility, a thermoplastic resin can be added.On the other hand, when the durability against solvents is required, athermoplastic resin is not preferably added.

The thermoplastic resin includes (meth)acryl base resins such aspoly(meth)acrylic acid esters and the like, polyvinyl acetal (butyralresins) such as polyvinyl butyral and the like, polyester resins such aspolyethylene terephthalate, polybutylene terephthalate and the like,vinyl chloride resins, urethane resins, polyolefins such aspolyethylene, polypropylene and the like, styrene base resins such aspolystyrene, poly-α-methylstyrene and the like, polyamides,polycarbonate, acetal resins such as polyoxymethylene and the like,fluororesins such as ethylene-ethylene tetrafluoride copolymers and thelike, polyimides, polylactic acid, polyvinyl acetal resins, liquidcrystalline polyester resins and the like. They may be used alone or incombination of two or more kinds thereof. When used in combination oftwo or more kinds thereof, they may be copolymers of monomersconstituting the above resins, or the respective resins may be used in amixture.

Among the thermoplastic resins described above, the resins comprising(meth)acryl base resins as principal components are preferred in thepresent invention, and among them, the resins obtained by polymerizingthe monomers comprising at least (meth)acrylic esters as the monomercomponents are preferred.

To be more specific, preferred are homopolymers of (meth)acrylic esters,copolymers of two or more kinds of different (meth)acrylic estermonomers and copolymers of (meth)acrylic esters with other monomers.

The thermoplastic resins described above have a weight average molecularweight falling in a range of 90,000 to 120,000. If the weight averagemolecular weight falls in the above range, all of the moldability aftercross-linking and curing to form the surface protective layer and anabrasion resistance and a scratch resistance of the surface can beobtained at high levels.

In this regard, the weight average molecular weight is apolystyrene-reduced value measured by gel permeation chromatography(GPC). A solvent used in the above case can suitably be selected fromsolvents usually used and includes, for example, tetrahydrofuran (THF),N-methyl-2-pyrrolidinone (NMP) and the like.

The thermoplastic resins described above have a polydispersion degree(weight average molecular weight Mw/number average molecular weight Mn)falling preferably in a range of 1.1 to 3.0. If the polydispersiondegree falls in the above range, all of the moldability aftercross-linking and curing to form the surface protective layer and anabrasion resistance and a scratch resistance of the surface can beobtained as well at high levels. From the viewpoint described above, apolydispersion degree of the above (meth)acryl base resins falls morepreferably in a range of 1.5 to 2.5.

Additives used for the ionizing radiation curable resin compositiondescribed above include, for example, weatherability improving agents,polymerization inhibitors, cross-linking agents, IR absorbing agents,antistatic agents, adhesion improving agents, leveling agents,thixotropy providing agents, coupling agents, plasticizers, defoamingagents, fillers, solvents, colorants, abrasion resistance improvingagents and the like.

Various additives can be added to the surface protective layer 15 thusformed to thereby impart various functions, for example, a so-calledhard coat function providing a high hardness and an abrasion resistance,a defogging function, a stain resistant function, a glare-prooffunction, an antireflective function, a UV shielding function, an IRshielding function and the like.

In the present invention, a thickness of the surface protective layer 15after cured is preferably 1 to 30 μm. If a thickness of the surfaceprotective layer 15 after cured is 1 μm or more, the excellent designproperties such as the transparence feeling, the gloss feeling and thelike are obtained, and the satisfactory physical properties of theprotective layer, such as a stain resistance, an abrasion resistance, aweatherability and the like are obtained. On the other hand, if it is 30μm or less, the protective layer is prevented from being cracked andwhitened in molding, and it can be endowed with a desired form andprovided with a good design property after three-dimensional molding.From the above viewpoints, a thickness of the surface protective layer15 after cured falls in a range of preferably 2 to 20 μm, morepreferably 3 to 10 μm.

Capable of being used as a binder resin used for the fineparticle-containing resin layer 16 are, for example, resins such aspolyolefin resins including polypropylene, polyethylene and the like,polyester resins, polyurethane resins, acryl base resins, acryl urethanebase resins, polycarbonate resins, vinyl chloride/vinyl acetatecopolymers, polyvinyl butyral resins, nitrocellulose resins (cellulosenitrate) and the like, in addition thereto, compounds such as alkyltitanate, ethyleneimine and the like. They can suitably be selected andused from the viewpoint of an adhesive property with the adherend andthe injection resin.

Capable of being used as fine particles used for the fineparticle-containing resin layer 16 are, for example, inorganic fineparticles of silica, talc, calcium carbonate, precipitated bariumsulfate, alumina, acid clay, clay, magnesium carbonate, carbon black,tin oxide, titan white, urea powder resins and the like, acryl beads andorganic fine particles comprising organic high polymers such aspolyethylene, urethane resins, polycarbonate, polyamide(nylon) and thelike. Among them, silica, acryl beads, polyethylene wax and the likewhich are readily handled and inexpensive are suited.

An average particle diameter of the fine particles is preferably 0.5 to20 μm, more preferably 0.5 to 10 μm, and an addition amount thereoffalls in a range of preferably 0.1 to 10 parts by mass, more preferably0.5 to 5 parts by mass based on 100 parts by mass of the binder resin. Aform of the particles is polyhedral, spherical, scaly and the like.

The decorative sheet 10 obtained by the production process of thepresent invention can be used for various injection molding methods suchas an insert molding method, an injection molding simultaneousdecoration method, a blow molding method, a gas injection molding methodand the like, and it can be used particularly suitably for the insertmolding method and the injection molding simultaneous decoration method.

In the insert molding method, the decorative sheet obtained by theproduction process of the present invention is subjected in advance tovacuum molding (offline preliminary molding) into a surface form of themolded article by means of a vacuum molding die in a vacuum moldingstep, and then surplus parts are trimmed, if necessary, to obtain amolded sheet. This molded sheet is inserted into an injection moldingdie, and the injection molding die is clamped. A resin staying in aflowing state is injected into the die and solidified, and thedecorative sheet is integrated with an outer surface of the resin moldedarticle at the same time as injection molding to produce a decoratedresin molded article.

Resins according to the uses are used for the injection resin, andrepresentative are polyolefin resins such as polypropylene, polyethyleneand the like and thermoplastic resins such as ABS resins, styreneresins, polycarbonate resins, acryl resins, vinyl chloride resins andthe like. Further, thermosetting resins such as urethane resins, epoxyresins and the like can be used as well according to the uses.

Next, in the injection molding simultaneous decoration method, thedecorative sheet of the present invention is disposed in a female dieused also as a vacuum molding die in which a vacuum port for injectionmolding is provided, and it is subjected to preliminary molding (inlinepreliminary molding) in the above female die. Then, the injectionmolding die is clamped, and a resin staying in a flowing state isinjected and filled into the die and solidified, whereby the decorativesheet is integrated with an outer surface of the resin molded article atthe same time as injection molding to produce a decorated resin moldedarticle.

In the injection molding simultaneous decoration method, heat andpressure are exerted on the decorative sheet by the injection resin, andtherefore the decorative sheet may be or may not be preliminarily heatedwhen it is close to a flat board and drawn to a small extent.

Also, the same resins as explained in the insert molding method can beused as the injection resin used above.

The decorated resin molded article produced in the above manner is amolded article which is excellent in a surface smoothness and a glossand which is provided with a high design property. Further, in theproduction process of the present invention, the surface protectivelayer is completely cured in a stage of producing the decorative sheet,and therefore a step in which the surface protective layer iscross-linked and cured after producing the decorated resin moldedarticle is not necessary.

EXAMPLES

Next, the present invention shall be explained in further details withreference to examples, but the present invention shall by no means berestricted by these examples.

The respective evaluation methods and measuring methods shall beexplained below in detail.

Arithmetic Average Roughness Ra:

Measured by means of a surface roughness measuring equipment (tradename: HANDYSURF E-35A) manufactured by Tokyo Seimitsu Co., Ltd.according to JIS B 601:2001, wherein a roughness curve having a length Lwas folded back at a central line, and a value obtained by dividing awhole area surrounded by the respective roughness curves and the centralline by the length L was shown by micrometer (μm).

Ten point average roughness Rz_(JIS):

The ten point average roughness Rz_(JIS) was measured at a measuringlength of 4 mm and a cutoff value of 0.8 mm according to JIS B 601:2001.

Blocking Resistance:

Two sheets of the decorative sheets were used, and a surface side of onesheet and a rear face side of the other sheet were superposed. A load of2.94 MPa was applied thereon by means of a blocking tester, and theywere left standing at 40° C. for 72 hours. Then, an adhering andsticking degree of the faces brought into contact with each other wasevaluated according to the following criteria.

∘: resistance was not observed at all when the superposed decorativesheets were peeled off.x: resistance was observed when the superposed decorative sheets werepeeled off, and scratches and wrinkles originating in blocking wereconfirmed on the surface side of the decorative sheet.

Wounds and Dents Produced by Foreign Matters:

The decorative sheet was wound in a roll form in which a surface side ofone layer and a rear face side of the other layer were superposed, andthe roll was left standing at 20° C. for 168 hours. Twenty sheets of thedecorative sheets were cut out of the roll to confirm the number of thesheets in which wounds and dents were observed on a surface protectivelayer. These wounds and dents were considered to be due to foreignmatters such as fine dusts and the like which were wrapped in the roll.

∘: decorative sheets in which wounds and dents were generated were zeroΔ: decorative sheets in which wounds and dents were generated were lessthan 10 sheetsx: decorative sheets in which wounds and dents were generated were 10 ormore sheets

Surface Gloss:

A gloss value was measured on the condition of an incident angle of 60°by means of a gloss meter (micro-TRI-gloss, manufactured by BYK GardnerInc.). It is shown that the higher the numerical value is, the higherthe gloss is.

Smoothness:

A surface of a molded article prepared by subjecting the decorativesheet to inset molding was visually evaluated.

∘: the surface was excellent in a smoothness, and clear images werereflected on a surface of the molded articlex: the surface was short of a smoothness, and images reflected on asurface of the molded article were distorted

Haze:

Evaluated by a haze value defined in ASTM D4039. The respective glossvalues were measured on the condition of an incident angle of 60° and20° by means of the gloss meter (micro-TRI-gloss, manufactured by BYKGardner Inc.) to determine the haze values according to the followingequation.

haze value=gloss value)(60°)−gloss value(20°)

It is shown that the smaller the haze value is, the higher the glossfeeling and the transparence feeling are and that the larger the hazevalue is, the lower the hazing transparency is.Adhesive Property with Injection Resin:

Cross-cut-shaped cuts were given on a surface of the sheet by 10 linesin a vertical direction and 10 lines in a lateral direction at aninterval of 2 mm by means of a utility knife after the insert molding,and then Sellotape (trade name) manufactured by Nichiban Co., Ltd. wasstuck tightly on the parts provided with the cuts and quickly peeledoff.

⊚: no peeling was observed∘: very slight peeling was observed along the cross-cut-shaped cutsx: peeling was observed between the sheet and the injection resin

Emboss Fastness:

The decorative sheet was dipped in an oil bath of a prescribedtemperature for 1 minute, and creping reversion of the emboss and agloss thereof after dipping were visually observed. They were evaluatedat every 10° C., and the highest temperature at which creping reversionwas not observed and at which the gloss was not changed was shown.

Example 1

A biaxially oriented polyethylene terephthalate film (thickness: 25 μm,arithmetic average roughness (Ra): 0.01 μm) having a release layer of asilicone base on a surface layer was used as a releasing film, and anacryl/urethane block copolymer resin was coated on the above releasingfilm to form a transparent primer layer having a thickness of 2 μm.

Then, a design layer of a woodgrain pattern was formed on the aboveprimer layer by gravure printing using an acryl urethane copolymer resinink. Thereafter, a design layer side of the sheet in which the primerlayer and the design layer were formed on the releasing film was broughtinto contact with a base material (a sheet comprising an ABS resin,thickness: 300 μm), and then the sheet was subjected to hot pressprocessing at 150° C. under applying a pressure of 5 kgf/cm² for 10minutes by means of a hot press machine in which a stainless-made mirrorsurface plate having an arithmetic average roughness Ra of 0.05 μm wasused for a primer layer side (surface side) and in which astainless-made metal plate provided with a satin finished pattern havingan arithmetic average roughness Ra of 4.0 μm and a ten point averageroughness RzJIS of 16 μm was used for a base material side (rear faceside). After the hot press processing, the releasing film was peeled offto transfer the primer layer and the design layer onto the basematerial.

Next, an ionizing radiation curable resin composition comprisingdifunctional urethane acrylate (weight average molecular weight: 2,000)was coated on a surface of the primer layer after the releasing film waspeeled off by gravure reverse so that a thickness thereof after curedwas 6 μm. The above uncured resin layer was irradiated with an electronbeam at an acceleration voltage of 165 kV and an irradiation dosage of50 kGy (5 Mrad) to cure the ionizing radiation curable resincomposition, whereby a decorative sheet was obtained.

The decorative sheet thus obtained had an arithmetic average roughnessRa of 0.1 μm at a surface side and 2.0 μm at a rear face side.

Next, the decorative sheet obtained was heated by means of an infraredheater until a temperature of the sheet reached 170° C. and softened,and then it was subjected to vacuum molding. The decorative sheet wasreleased from the die, and a rear face thereof was confirmed to findthat the emboss disappeared and that the sheet was flattened.Unnecessary parts of the decorative sheet subjected to vacuum moldingwere trimmed by pressing a die cut mold against it by applying an oilpressure. The above decorative sheet trimmed was inserted into aninjection molding die, and then the die was clamped. An ABS resin wasinjected into the die, and the decorative sheet was laminated on asurface of the molded article and integrated therewith to obtain adecorative resin molded article by insert molding.

Example 2

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 1, except that a stainless-made metalplate provided with a satin finished pattern having an arithmeticaverage roughness Ra of 8.5 μm and a ten point average roughness RzJISof 39 μm was used for a side (rear face side) having no design layer inthe hot press step.

Example 3

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 1, except that a sheet comprising anABS resin having a thickness of 200 μm was used for the base materialand that a stainless-made metal plate provided with a satin finishedpattern having an arithmetic average roughness Ra of 6.9 μm and a tenpoint average roughness RzJIS of 28 μm was used for a side (rear faceside) having no design layer in the hot press step.

Example 4

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 1, except that a sheet comprising anABS resin having a thickness of 400 μm was used for the base materialand that a stainless-made metal plate provided with a satin finishedpattern having an arithmetic average roughness Ra of 4.0 μm and a tenpoint average roughness RzJIS of 23 μm was used for a side (rear faceside) having no design layer in the hot press step.

Example 5

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 1, except that a sheet comprising anABS resin having a thickness of 400 μm was used for the base materialand that used was an ionizing radiation curable resin compositionobtained by mixing difunctional polycarbonate acrylate (weight averagemolecular weight: 10,000) and hexafunctional urethane acrylate (weightaverage molecular weight: 6,000) in a ratio of 94:6.

Example 6

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 1, except that a sheet comprising anABS resin having a thickness of 400 μm was used for the base materialand that used was an ionizing radiation curable resin compositionobtained by mixing difunctional acryl silicone acrylate (weight averagemolecular weight: 20,000) and hexafunctional urethane acrylate (weightaverage molecular weight: 5,000) in a ratio of 70:30.

Comparative Example 1

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 1, except that in the hot pressprocessing in Example 1, the hot press processing was carried out at140° C. by using a stainless-made metal plate provided with a satinfinished pattern having an arithmetic average roughness Ra of 19 μm anda ten point average roughness RzJIS of 130 μm.

Comparative Example 2

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 1, except that a sheet comprising anABS resin having a thickness of 200 μm was used for the base materialand that in the hot press processing in Example 1, the hot pressprocessing was carried out by using a stainless-made mirror surfaceplate having an arithmetic average roughness Ra of 1.8 μm and a tenpoint average roughness RzJIS of 6 μm for a rear face side in place ofthe stainless-made metal plate provided with a satin finished pattern.

Comparative Example 3

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Comparative Example 1, except that inComparative Example 2, a sheet comprising an ABS resin having athickness of 400 μm was used for the base material and that acomposition comprising 100 parts by mass of an acryl base resin and 10parts by mass of silica (average particle diameter: 3.0 μm) was coatedon a surface side in a coating amount of 1 g/m² by gravure printing toprovide a fine particle-containing resin layer.

Comparative Example 4

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 5, except that a sheet comprising anABS resin having a thickness of 100 μm was used for the base materialand that in the hot press processing in Example 1, the hot pressprocessing was carried out by using a stainless-made mirror surfaceplate having an arithmetic average roughness Ra of 28.2 μm and a tenpoint average roughness RzJIS of 97 μm for a rear face side in place ofthe stainless-made metal plate provided with a satin finished pattern.

Next, an arithmetic average roughness Ra and a ten point averageroughness Rz on a surface and a rear face of the decorative sheetsprepared in Examples 1 to 6 and Comparative Examples 1 to 4 weremeasured, and an emboss fastness on a rear face thereof was measured.The results thereof are shown in Table 1 and Table 2. In addition to theabove, evaluated were a blocking resistance and wounds and dentsgenerated by foreign matters in the decorative sheets obtained inExamples 1 to 6 and Comparative Examples 1 to 4 and a surface gloss, asmoothness, a haze and an adhesive property with the injection resin inthe decorative resin molded articles. The results thereof are shown inTable 1 and Table 2.

TABLE 1 Example 1 2 3 4 5 6 Sheet Thickness of base material 300 300 200400 400 400 constitution (μm) Surface Arithmetic 0.1 0.1 0.1 0.1 0.1 0.1average roughness Ra (μm) Ten point 1.0 2.0 2.0 1.0 1.0 1.0 averageroughness Rz (μm) Rear Arithmetic 2.0 7.0 5.0 3.0 2.0 2.0 face averageroughness Ra (μm) Ten point 14 31 22 19 9.0 11 average roughness Rz (μm)Evaluation Decorative Blocking ◯ ◯ ◯ ◯ ◯ ◯ items sheet resistance Woundsand dents ◯ ◯ ◯ ◯ ◯ ◯ generated by foreign matters Decorative Surfacegloss 88 84 84 88 90 91 resin Smoothness ◯ ◯ ◯ ◯ ◯ ◯ molded Haze 6 14 148 6 8 article Adhesive ◯ ◯ ◯ ◯ ◯ ◯ property with injection resin

TABLE 2 Comparative Example 1 2 3 4 Sheet Thickness of base material 300200 400 100 constitution (μm) Surface Arithmetic 2.5 0.1 4.0 0.1 averageroughness Ra (μm) Ten point average 15 0.1 20 1.0 Rz roughness (μm) Fineparticles None None Silica None (average particle (3.0 μm) diameter)Rear Arithmetic 18 0.3 0.1 25 face average roughness Ra (μm) Ten pointaverage 103 2 1 82 Rz roughness (μm) Evaluation Decorative Blocking ◯ X◯ ◯ items sheet resistance Wounds and dents ◯ X ◯ ◯ generated by foreignmatters Decorative Surface gloss 71 88 65 68 resin Smoothness X ◯ X ◯molded Haze 22 2 42 50 article Adhesive property ◯ ◯ ◯ ◯ with injectionresin

Example 7

A biaxially oriented polyethylene terephthalate film (thickness: 25 μm,arithmetic average roughness (Ra): 0.01 μm) having a release layer of asilicone base on a surface layer was used as a releasing film, and anacryl/urethane block copolymer resin was coated on the above releasingfilm to form a transparent primer layer having a thickness of 2 μm.

Then, a design layer of a woodgrain pattern was formed on the aboveprimer layer by gravure printing using an acryl urethane copolymer resinink. Thereafter, a design layer side of the sheet in which the primerlayer and the design layer were formed on the releasing film was broughtinto contact with a base material (a sheet comprising an ABS resin,thickness: 400 μm), and then the sheet was subjected to hot pressprocessing at 150° C. under applying a pressure of 5 kgf/cm² for 10minutes by means of a hot press machine in which a stainless-made mirrorsurface plate having an arithmetic average roughness Ra of 0.05 μm wasused for a primer layer side (surface side) and in which astainless-made metal plate provided with a satin finished pattern havingan arithmetic average roughness Ra of 8.0 μm was used for a basematerial side (rear face side). After the hot press processing, thereleasing film was peeled off to transfer the primer layer and thedesign layer onto the base material.

Next, an ionizing radiation curable resin composition comprisingdifunctional urethane acrylate (weight average molecular weight: 2,000)was coated on a surface of the primer layer after the releasing film waspeeled off by gravure reverse so that a thickness thereof after curedwas 6 μm. The above uncured resin layer was irradiated with an electronbeam at an acceleration voltage of 165 kV and an irradiation dosage of50 kGy (5 Mrad) to cure the ionizing radiation curable resincomposition, whereby a decorative sheet was obtained.

The decorative sheet thus obtained had an arithmetic average roughnessRa of 0.1 μm at a surface side and 3.0 μm at a rear face side. Also, ithad an emboss fastness of 130° C.

Next, the decorative sheet obtained was heated by means of an infraredheater until a temperature of the sheet reached 170° C. and softened,and then it was subjected to vacuum molding. The decorative sheet wasreleased from the die, and a rear face thereof was confirmed to findthat the emboss disappeared and that the sheet was flattened.Unnecessary parts of the decorative sheet subjected to vacuum moldingwere trimmed by pressing a die cut mold against it by applying an oilpressure. The above decorative sheet trimmed was inserted into aninjection molding die, and then the die was clamped. An ABS resin wasinjected into the die, and the decorative sheet was laminated on asurface of the molded article and integrated therewith to obtain adecorative resin molded article by insert molding.

Example 8

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 7, except that a temperature of the hotpress was changed to 140° C.

Example 9

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 7, except that a temperature of the hotpress was changed to 180° C.

Example 10

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 7, except that a temperature of the hotpress was changed to 230° C.

Example 11

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 7, except that in the hot pressprocessing in Example 7, a stainless-made mirror surface plate having anarithmetic average roughness Ra of 0.05 μm was used for a rear face sidein place of the stainless-made metal plate provided with a satinfinished pattern and that after curing the ionizing radiation curableresin composition on the surface, a composition comprising 100 parts bymass of an acryl base resin and 3 parts by mass of silica (averageparticle diameter: 1.5 μm) was coated on a rear face side in a coatingamount of 1 g/m² by gravure printing to provide a fineparticle-containing resin layer.

Example 12

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 11, except that silica having anaverage particle diameter of 3.0 μm was used in place of silica havingan average particle diameter of 1.5 μm.

Example 13

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 11, except that silica having anaverage particle diameter of 5.0 μm was used in place of silica havingan average particle diameter of 1.5 μm.

Example 14

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 11, except that acryl beads having anaverage particle diameter of 5.0 μm were used in place of silica havingan average particle diameter of 1.5 μm.

Example 15

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 11, except that polyethylene wax havingan average particle diameter of 5.0 μm was used in place of silicahaving an average particle diameter of 1.5 μm.

Example 16

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 7, except that used was an ionizingradiation curable resin composition obtained by mixing difunctionalpolycarbonate acrylate (weight average molecular weight: 10,000) andhexafunctional urethane acrylate (weight average molecular weight:6,000) in a ratio of 94:6.

Example 17

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 7, except that used was an ionizingradiation curable resin composition obtained by mixing difunctionalacryl silicone acrylate (weight average molecular weight: 20,000) andhexafunctional urethane acrylate (weight average molecular weight:5,000) in a ratio of 70:30.

Comparative Example 5

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 7, except that in the hot pressprocessing in Example 7, the hot press processing was carried out byusing a stainless-made mirror surface plate having an arithmetic averageroughness Ra of 0.05 μm for a rear face side in place of thestainless-made metal plate provided with a satin finished pattern.

Comparative Example 6

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 7, except that in the hot pressprocessing in Example 7, the hot press processing was carried out at140° C. by using a stainless-made metal plate provided with a satinfinished pattern having an arithmetic average roughness Ra of 19 μm fora rear face side.

Comparative Example 7

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Comparative Example 5, except that inComparative Example 5, a composition comprising 100 parts by mass of anacryl base resin and 10 parts by mass of silica (average particlediameter: 3.0 μm) was coated on a surface side in a coating amount of 1g/m² by gravure printing to provide a fine particle-containing resinlayer.

Comparative Example 8

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 11, except that silica having anaverage particle diameter of 0.1 μm was used in place of silica havingan average particle diameter of 1.5 μm.

Comparative Example 9

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Example 11, except that silica having anaverage particle diameter of 9.0 μm was used in place of silica havingan average particle diameter of 1.5 μm.

Comparative Example 10

A decorative sheet and a decorative resin molded article were obtainedin the same manner as in Comparative Example 5, except that inComparative Example 5, an isopropyl alcohol 10% solution of a cationicsurfactant (trimethylammonium dimethylsulfate) as an antistatic agentwas coated on a rear face side by gravure coating so that a coatingthickness thereof in drying was 0.5 g/m³.

An arithmetic average roughness Ra and a ten point average roughness Rzon a surface and a rear face of the decorative sheets prepared inExamples 7 to 17 and Comparative Examples 5 to 10 were measured, and anemboss fastness on a rear face thereof was measured. The results thereofare shown in Table 3 to Table 5. In addition to the above, evaluatedwere a blocking resistance and wounds and dents generated by foreignmatters in the decorative sheets obtained in Examples 7 to 17 andComparative Examples 5 to 10 and a surface gloss, a smoothness, a hazeand an adhesive property with the injection resin in the decorativeresin molded articles. The results thereof are shown in Table 3 to Table5.

TABLE 3 Example 7 8 9 10 11 12 13 14 15 Sheet Surface Arithmetic 0.1 0.10.1 0.1 0.1 0.1 0.1 0.1 0.1 constitution average roughness Ra (μm) Tenpoint 1 1 1 1 1 1 1 1 1 average roughness Rz (μm) Fine particle NoneNone None None None None None None None Rear Arithmetic 3 1.5 5 7 1 4 67 6 face average roughness Ra (μm) Ten point 13 10 27 35 — — — — —average roughness Rz (μm) Emboss fastness 130° C. 120° C. 140° C. 200°C. — — — — — (° C.) Fine particle None None None None Silica SilicaSilica Acryl Poly (average particle (1.5 μm) (3.0 μm) (5.0 μm) beadsethylene diameter) (5.0 μm) wax (5.0 μm) Evaluation Decorative Blocking◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ items sheet resistance Wounds and ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯dents generated by foreign matters Decorative Surface gloss 90 91 88 8589 87 90 89 89 resin Smoothness ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ molded Haze 5.9 5.76.1 6.9 5.7 5.8 6.0 6.2 7.3 article Adhesive property ⊚ ⊚ ⊚ ◯ ◯ ◯ ◯ ◯ ◯with injection resin

TABLE 4 Example 16 17 Sheet Surface Arithmetic 0.1 0.1 constitutionaverage roughness Ra (μm) Ten point average 1 1 roughness Rz (μm) Fineparticles None None (average particle diameter) Rear face Arithmetic 21.5 average roughness Ra (μm) Ten point average 12 11 roughness Rz (μm)Emboss fastness 130° C. 130° C. (° C.) Fine particles None None (averageparticle diameter) Evaluation Decorative Blocking ○ ○ items sheetresistance Wounds and dents ○ ○ generated by foreign matters DecoratedSurface gloss 90 91 resin Smoothness ○ ○ molded Haze 5.7 4.9 articleAdhesive property ⊚ ⊚ with injection resin

TABLE 5 Comparative Example 5 6 7 8 9 10 Sheet Surface Arithmeticaverage roughness 0.1 2.3 4 0.1 0.1 0.1 constitution Ra (μm) Ten pointaverage roughness 1 15 20 1 1 1 Rz (μm) Fine particles None None SilicaNone None None (average particle (3.0 μm) diameter) Rear Arithmeticaverage roughness 0.1 13 0.1 0.2 13 0.1 face Ra (μm) Ten point averageroughness 1 60 1 — — — Rz (μm) Emboss fastness (° C.) — 140° C. — — — —Fine particles None None None Silica Silica None (average particlediameter) (0.1 μm) (9.0 μm) Surfactant None None None None None PresentEvaluation Decorative Blocking resistance X ◯ ◯ X ◯ ◯ items sheet Woundsand dents generated by X ◯ ◯ X Δ Δ foreign matters Decorative Surfacegloss 92 80 65 88 85 89 resin Smoothness ◯ X X ◯ ◯ ◯ molded Haze 5.9 3042 6.2 9.5 6.0 article Adhesive property with ◯ ◯ ◯ ◯ X X injectionresin

As shown in Table 1 and Table 2, the decorative sheets prepared inExamples 1 to 6 did not generate blocking and dents and wounds bywrapping therein foreign matters even when winding them on a roll. Incontrast with this, in Comparative Example 1 in which T×0.30<RzJIS wasshown, a smoothness on a surface of the decorated resin molded articlewas damaged. On the other hand, in Comparative Example 2 in whichRa<T×0.005 was shown, blocking and dents and wounds by wrapping thereinforeign matters were generated.

Also, in Comparative Example 3 in which the fine particle-containingresin layer was provided on a surface side of the decorative sheet, asmoothness on a surface of the decorative resin molded article wasdamaged.

In Comparative Example 4, Ra and RzJIS were too large, and therefore agloss on a surface of the decorative resin molded article was notablyreduced to generate a haze.

Also, as shown in Table 3 to Table 5, the decorative sheets prepared inExamples 7 to 17 did not generate blocking and dents and wounds bywrapping therein foreign matters even when winding them on a roll. Incontrast with this, in Comparative Examples 5 and 9 in which anarithmetic average roughness Ra on the rear face was less than 1.0 μm,blocking and dents and wounds by wrapping therein foreign matters weregenerated. On the other hand, in Comparative Examples 6 and 9 in whichan arithmetic average roughness Ra on the rear face exceeded 10.0 μm,brought about were the problems that a smoothness on a surface of thedecorative sheet was damaged and that the adhesive property with theinjection resin was reduced.

Also, in Comparative Example 7 in which the fine particle-containingresin layer was provided on a surface side of the decorative sheet, asmoothness on a surface of the decorative sheet was damaged.

In Comparative Example 10, blocking was inhibited by coating thesurfactant on a rear face side of the decorative sheet, but since bothsurfaces of the decorative sheet were smooth, dents and wounds caused bywrapping therein foreign matters could not completely be prevented, andthe adhesive property with the injection resin was reduced.

INDUSTRIAL APPLICABILITY

The decorative sheets obtained by the production process of the presentinvention are suitably used for decorative resin molded articlesincluding, for example, interior materials or exterior materials ofvehicles and the like, fixture members such as skirting boards, cornicesand the like, fittings such as window frames, door frames and the like,interior materials for buildings such as walls, floors, ceilings and thelike, housings and vessels for home electric appliances such as TVreceivers, air conditioners and the like.

What is claimed is:
 1. A decorative sheet comprising a design layer, aprimer layer and a surface protective layer formed by cross-linking andcuring an ionizing radiation curable resin composition in this order ona base material, wherein a surface of the surface protective layer issmooth; a ten point average roughness RzJIS on a rear face of thedecorative sheet and a thickness T of the base material satisfies thefollowing equation (I); and an arithmetic average roughness Ra on therear face and a thickness T of the base material satisfies the followingequation (II):T×0.30≧RzJIS  (I)T×0.20≧Ra≧T×0.005  (II).
 2. The decorative sheet according to claim 1,wherein an arithmetic average roughness Ra of the surface protectivelayer is 0.01 μm or more and less than 1.0 μm.
 3. A decorative moldedarticle prepared by using the decorative sheet according to claim
 2. 4.A decorative molded article prepared by using the decorative sheetaccording to claim
 1. 5. A decorative sheet comprising a design layer, aprimer layer and a surface protective layer formed by cross-linking andcuring an ionizing radiation curable resin composition in this order ona base material, wherein a surface of the surface protective layer issmooth, and an arithmetic average roughness Ra on a rear face of thedecorative sheet is 1.0 to 10.0 μm.
 6. The decorative sheet according toclaim 1, wherein an arithmetic average roughness Ra of the surfaceprotective layer is 0.01 μm or more and less than 1.0 μm.
 7. Adecorative molded article prepared by using the decorative sheetaccording to claim
 6. 8. A decorative molded article prepared by usingthe decorative sheet according to claim 5.